Dataset Information

Mechanism of BceAB-type transporter: Resistance by lipid II flipping

ABSTRACT: Treatment of bacterial infections are the great challenge of our era due to the evolved resistance mechanisms against antibiotics. The Achilles heel of bacteria is the cell wall especially during the needs of its synthesis and cell division. Here lipid II is an essential precursor component synthesized in the cytosol and flipped into the outer leaflet of the membrane prior to application into the cell wall. Compounds targeting the cell wall or its biosynthesis precursors have been around for decades and have been used as antibiotics against bacterial infections like meningitis, pneumonia and endocarditis. In the last decades however resistance against those antibiotics evolved and antimicrobial peptides (AMPs) have been found to be promising alternative antibiotics. The Bacitracin efflux (BceAB)-type ATP binding cassette transporters expressed in the membrane of human pathogenic bacteria confer resistance against these alternative antibiotics and thereby their medical development is hampered. Here we elucidated the mechanism of the BceAB-type transporter NsrFP from Streptococcus agalactiae COH1 (SaNsrFP), described to confer high resistance against the antimicrobial peptide nisin, a member of the lantibiotic subfamily. We showed that SaNsrFP is using a novel mechanism of resistance by flipping lipid II back into the cytosol thereby preventing the binding of nisin as well as other lipid II targeting compounds. This trick is intriguing since it uses a relative simple mechanism resulting in the resistance of the human pathogenic bacteria against a structurally divers group of potent antibiotics.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Lactococcus Lactis Subsp. Cremoris Nz9000 Bacteria

SUBMITTER: Nina Overbeck

LAB HEAD: Kai Stühler

PROVIDER: PXD017318 | Pride | 2022-04-04

REPOSITORIES: pride

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New insights into the resistance mechanism for the BceAB-type transporter SaNsrFP.

Gottstein Julia J Zaschke-Kriesche Julia J Unsleber Sandra S Voitsekhovskaia Irina I Kulik Andreas A Behrmann Lara V LV Overbeck Nina N Stühler Kai K Stegmann Evi E Smits Sander H J SHJ

Scientific reports 20220310 1

Treatment of bacterial infections is one of the major challenges of our time due to the evolved resistance mechanisms of pathogens against antibiotics. To circumvent this problem, it is necessary to understand the mode of action of the drug and the mechanism of resistance of the pathogen. One of the most potent antibiotic targets is peptidoglycan (PGN) biosynthesis, as this is an exclusively occurring and critical feature of bacteria. Lipid II is an essential PGN precursor synthesized in the cyt ...[more]

PMID: 35273305

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Project description:The two-component system (TCS) is a specific regulatory system in bacteria and plays an important role in sensing and adapting to the environment. In this study, we evaluated the roles of TCSs in the major cariogenic pathogen Streptococcus mutans in resistance to several types of bacteriocin. In a comprehensive analysis using individual TCS mutants, we found that two novel TCSs were associated with resistance against distinct lantibiotics nisin A (class I type A[I]) and nukacin ISK-1(class I type A[II]). One TCS, SMU.659-660 (designated as NsrRS), was related to resistance against nisin A produced by Lactococcus lactis ATCC 11454. The other TCS, SMU.1146-1145 (designated as LcrRS), was related to resistance against nukacin ISK-1 produced by Staphylococcus warneri ISK-1. NsrRS induced the expression of SMU.658 (designated as NsrX), which constitutes an operon with nsrRS, in response to nisin A. Inactivation of nsrX increased susceptibility to nisin A. Additionally, NsrX expression in S. mutans increased the binding affinity to nisin A compared to a no-expression strain. LcrRS induced the expression of SMU.1148-50 (lctFEG), which encodes an ABC transporter and is located upstream of lcrRS, in response to nukacin ISK-1. Inactivation of lctFEG significantly increased susceptibility to nukacin ISK-1. Electrophoretic mobility shift assay analysis revealed that NsrR and LcrR bound directly to regions upstream of nsrX and lctFEG, respectively. This is the first report that two distinct TCSs, NsrRS and LcrRS, are independently involved in resistance to nisin A and nukacin ISK-1 in S. mutans. Total of 14 samples were analyzed. Total RNA from each test strain and control described below were labeled with Alexa FluorÂ® 555 and Alexa FluorÂ® 647, respectively, and were cohybridized on a single array. Labeling and hybridization were performed once or twice independently. UA159 wild type as control vs. UA159 with nisinA or nukacin ISK-1, UA159 wild type with nisinA or nukacin ISK-1 vs. nsrRS or lcrRS deletion mutant in UA159 with nisinA or nukacin ISK-1.

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